Many organisms have evolved a fibrillated interface for controlled contact and adhesion. As discussed in WO 01/49776, for example, the Gecko lizard appears to have evolved the ability to create dry, re-applicable adhesion to a variety of surfaces by relying only on weak van der Waals forces. Despite the low intrinsic energy of separating surfaces held together by van der Waals forces, these organisms are able to achieve remarkably strong adhesion. The microstructure employed by the Gecko, consisting of fibrils called setae and spatulae, plays a critical role in this ability.
Processes disclosed in WO 01/49776 describe replicating the natural structure of the gecko's foot by casting the structure, generally from a mold. This involves creating a template on a micro scale, placing the material from which the structure is to be fabricated into the mold, and then either extracting the structure, or dissolving the mold away.
A need remains, however, for processes that are more versatile than those known in the art by which a fibrillar microstructure may be prepared. The improved processes of this invention enable the production of new kinds of fibrillar microstructures.